Hydraulic compressor



July 26,1955 F. R. HOOP 2,713,827

HYDRAULIC COMPRESSOR Filed Sept. 29, 1952 3/31 32 35 INVENTOR.

3b LBW ATTORNEY United States Patent HYDRAULIC COMPRESSOR Frederick R.Hoop, Grand Rapids, Micln, assignor of onehalf to Samuel M. Koukios,Grand Rapids, Mich.

Application September 29, 1952, Serial No. 312,035

Claims. (Cl. 103-44) The present invention relates to a particularlynovel and effective compressor pump by means of which a fluid, gaseousor liquid, may be pumped into a container or the like, the compressedgaseous fluid or a fluid of mixed gaseous and liquid constituentsreaching a very high pressure. against strong back pressure or heads,that is, the liquid can be pumped to high elevations against the backpressure of the head, the pump being usable from a standing startagainst heavy pressures without danger of stalling or otherwise becominginoperative. the pump is driven by an electric motor, any blocking orstalling taking place in the pump with the current being supplied to theelectric motor would result in serious damage to the motor. With thepump which I have invented it can be started under low torque againsthigh pressure and will start and be driven by an electric motor even Thepump is also usable for pumping liquids In many cases where though theback pressure against which it is operating is high, reaching to morethan 250 pounds per square inch.

It is an object and purpose of my invention to provide a simple,effective, relatively low cost, sturdy and durable pump having thedesirable characteristics and advantages stated, an understanding ofwhich may be had from the following description, taken in connectionwith the accom panying drawing, in which,

Fig. 1 is a plan view of a pump unit which is located within asurrounding housing or casing therewith and is associated with an inletand outlet fluid control underneath it in the completed pump.

Fig. 2 is a generally central vertical section through the assembledpump, the plane of the section being substantially that shown on theline 22 of Fig. l, and

Fig. 3 is a similar vertical section substantially on the plane of line3-3 of Fig. 1.

Like reference characters refer to like parts in the different figuresof the drawing.

In the construction of the pump, a hollow housing or casing 1 ofgenerally cylindrical form, vertically positioned and open at both endsis closed at its'upper end by a flat closure plate 2, screw connectedthereto. At a side and adjacent the upper end of the housing or casing 1is an opening closed by a vertical plate 3 which has a journal bearingtherethrough for a driving shaft 4, rotatably mounted in and extendingthrough the bearing and which is adapted to be driven by an electricmotor.

At the inner end of the shaft, a disk 5 is permanently secured and to ita connecting rod 6 is pivotally mounted off-center from the shaft 4,there being formed a crankshaft which will vertically reciprocate apiston secured to the lower end of the connecting rod 6 when the shaft 4is driven.

In the lower end portion of the casing or housing 1, a pumping unit islocated having a horizontal base 7 with a downturned annular flange atits edges from the central portion of which a vertical cylinder 8, openat both ends, extends upwardly and within which a valveless piston 9 ismounted for reciprocation. The piston 9 is operatively connected to thelower end of the connectingrod 6 and Patented July 26, 1955 ice moves upand down in the cylinder 8 upon rotation of the shaft 4.

A somewhat elongated tube 10 is secured at one end to the base 7 of thepumping unit at a side of the cylinder 8 having a capillary passagetherethrough, that is, a passage of small diameter not in generalexceeding approximately .020". The free end of this tube terminateswithin the casing 1 above the plate 7. The tube is bent and curved so asto supply the requisite length thereof within the space limits provided.This tube is a restrictor tube for low starting torque as will hereafterappear.

A second tube 11 is connected at one end with and passes through thebase plate 7, it having a passage therethrough which may approximate.070 in diameter leading to and connecting with a vertical tubularmember 12, the lower end of which is to one side of the cylinderSopposite Where the tube 11 is connected to the base 7, and is secured tosaid base as shown in Fig. 2. The tube 12 is in eflect a cylinder. Ithas an opening in its side directly opposite where the tube 11 isconnected with such cylinder 12 and above the tube 11 and the opening 13two openings 14, opposed to each other are made through the tubularcylinder 12. A plug 15 closes the upper end of the cylinder 12 fromwhich a long central spring guide 16 extends downwardly around which isa coiled compression spring 17. The tubular cylinder 12 immediatelybelow the upper end of the plug 15 has other openings or passages 18through its sides as shown.

In the lower end of the tubular cylinder 12 is a piston 19 the lower endof spring 17 bearing thereagainst. Plate 7 has an opening 20 ofrestricted size, in practice approximately .040 in diameter, directlyunder the piston 19.

At another place at the upper side of the plate 7, shown asdiametrically opposite the capillary tube 10, a short cylinder 21 issecured at its lower end to said plate 7, which plate has a verticalopening 22 therethrough located generally centrally of the cylinder 21.A loose valve 23 is located in the cylinder 21 and is normally held indown position by a coiled spring 21a pressing thereagainst at its upperside. In its lower position the valve 23 closes openings 24 made throughthe sides of the cylinder 21,

but when the piston is elevated above said openings they are uncovered.The spring 210 is compressed by a screw plug 25 threaded into the upperend of the cylinder 21, it being evident that the pressure force of thespring 21a may be adjusted by changing the position of the plug 25.

The pump housing or casing 1 is closed at its lower end by a lower endplate 26 secured thereto, between which and the lower end of the housing1 is a diaphragm 27 and above it a flat washer or ring gasket 28, suchgasket 28 having a large central opening therethrough. Between the inneredge portions of the gasket 28 and the lower edges of such downturnededge flanges of the plate 7 a transverse plate 29, having alarge numberof closely spaced small vertical openings 30 therethrough, is locatedbeing clamped in place when the closure 26 is assembled with the rest ofthe structure. The perforated plate 29 at its under side has asubstantially large shallow concave recess therein reaching at its edgesto and beyond the adjacent edge portions of the gasket 23, the upperside of the end closure plate 26 is recessed downwardly so that thediaphragm 27, when not in use, traverses a chamber divided into twosections, one above and one below the diaphragm as shown in Figs. 2 and3.

The lower closure plate 26 has a fluid inlet passage at 31 leading tothe chamber below the diaphragm with a valve 32 at the inner end of thepassage 31 which is adapted to have movement between its lowermostposition, when it closes such passage, and an upper stop plate 33 (Fig.3). It is evident when the pump 9 is mov ing on its upstroke and thediaphragm is flexed upwardly there will be a vacuum created below thediaphragm so that the valve 32 is lifted by fluid, gaseous or liquid,which may pass through the passage 1 and fill the chamber below thediaphragm.

The plate 26 is also provided with a fluid outlet or exhaust passage 34which has a second valve 35 across it normally actuated to close it bythe spring 36, as in Fig. 3. On the upstroke of the piston the valvecloses the passage 34 to the chamber below the diaphragm 27 but on thedownstroke of the piston 9, valve 32 being automatically closed, thecompressed fluid will act against the valve 35 to open it for itsoutward passage through the exhaust passage 34.

In the operation the pump casing is filled with a suitable liquid,generally oil, to a level above the upper end of the cylinder 8. Thecylinder 8 has transverse passages 37 through its walls which arelocated at a level such that when the piston 9 reaches its uppermostpoint of travel its lower end is above said openings 37. The space orchamber below the piston 9 and above and below the plate 29 and abovethe diaphragm 27 is also filled with oil or equivalent liquid.

In many cases, for example, in refrigeration apparatus, the fluid pumpedwill be against an initial heavy pressure. The automatic control of themotor which drives the shaft 4 will result in the pump being operated attimes with periods of no operation when the electric motor is at rest.The initial starting up of the pump will require that the piston shallreciprocate irrespective of the relatively heavy back pressure againstwhich it must work. In the operation of the pump with incompressibleliquid being acted upon by the piston 9 above the diaphragm 27, whenback pressure is low there will be a downward flexing of the diaphragm27 to force liquid out through the passage 34 with a limited flow ofliquid through the tube 11 and outwardly through the openings at 13.Practically no liquid will flow through the tube 10 because of thecapillarity of the passage through it. Of course the length of the tube10 may be varied so that flow of liquid through the tube will start atincreasing higher pressures the longer the tube may be. As the initialpressure against which the pump starting must act is raised, the piston19 will act against a relatively light coiled spring 17 so as to coverthe ports at 13, 14 and if the motor is not stopped, stalling the pump,the valve at 23 acting against a much heavier spring 21a will be liftedto uncover the openings at 24.

By adjusting the adjusting nut at 25 a higher pressure can be reached,this after the pump is in full operation,

and the motor running freely, though there would be a stalling if therewas a heavy back pressure against which the stationary motor would haveto work on starting. Such heavy back pressure is relieved in part by theflpw through the tube 11 until such time as the piston 19 is lifted toits position to close the ports at 13. If the tube at 11 had noconnection whatsoever with the cylinder 12 the flow of liquid through itwould continue all of the time instead of only a very short time ofmomentarily releasing of pressure.

When the pump starts at very high pressure initially,

the piston at 19 is lifted rapidly. But if that was all there was to thestructure, when the pressure was initially high there would not besutficient time of relief for the motor to pick up speed. However, withthe addi tional flow through the capillary tube 11, operating at highpressures, but practically not operating at all at lower pressuresbecause of the fineness of the capillary tube through it, there is asufiicient relief to the incompressibility of the liquid acted upon bythe piston 9 that the motor will continue to move and not be stalledbecause of liquid incompressibility, as it otherwise would be in theabsence of the relief aiforded by the capillary tube 11. The valve at 23is a limit valve to the ultimate pressure of liquid passing outwardly atthe outlet passage 34, against back pressure therein.

When any pump of the hydraulic type operates against low pressure, orpractically that of the atmosphere at start, it can get under way andits momentum carry it over dead center positions; and the pressurebuilds up, the motor running faster and attaining its full speed longbefore the highest limit of pressure is reached. To provide a limit ofpressure valve 23 will open at greater or less pressures dependent uponthe adjustment of. spring 21a. The initial getting under the way andbuilding up a momentum in the pump is through the flow of liquid throughthe pipe 11 freely into the tube 12 and out through the ports above thevalve 19. This however would be defective and not secure the results ifsuch flow continued indefinitely. For if the flow was suflicient so thatthe motor could start right off aaginst heavy back pressure the flowwould stay continuous and no pumping result but mere circulation withinthe pump. The getting under way and the momentum obtained occurs asthough the motor was starting against a relatively low pressure and notthe full back pressure which there may be in the outlet at 34 andagainst which the pump must eventually work, when, with the increasingrapidity of movement of the motor and piston 9, pressure will be builtup. As such pressure builds flow from the pipe 11 is closed by thelifting of the piston valve 19. Thereupon any further relief needed, ifthe back pressure is sufficiently high, is afforded by the capillarytube 11 and, finally, when the pressure to which the pump is adjusted bythe nut 25 against the spring 25a is reached, that is the ultimatepressure of the pump and it will maintain such pressure though there isa minor or continuous flow of liquid through the capillary tube 10.

The pump shown and described has been built and fully tested and triedand is exceptionally satisfactory. One place of very desirable use forthe pump is in conjunction with the compressor of refrigerating systemsin household and other refrigerators. It eliminates the sealing-in ofparts which is now an expensive and unsatisfactory structure. The pumpis safeguarded against '1 stalling as previously stated, and is sure andcertain in its operation under all conditions of pressure, under alltorque conditions, in fact under all of the conditions which are metwith in its use and operation.

The invention is defined in the appended claims and is to be consideredcomprehensive of all forms of structure coming within their scope.

I claim:

1. In a pump having a casing with a chamber therein for fluid to bepumped, said chamber having inlet and outlet passages with inlet andoutlet valves therein, and a diaphragm comprising the upper side of saidcasing over said chamber, the improvement comprising, a hollow, verticalhousing, adapted to contain liquid, located over said diaphragm andagainst its peripheral edge portions, a

vertical cylinder within said housing, a horizontal base at the lowerend of said cylinder over said diaphragm, means between said base anddiaphragm for providing a chamber communicating with the lower end ofsaid cylinder, for liquid over the diaphragm, a piston in the cylinder,means for reciprocating the piston, spring loaded valve means mounted onand above said base normally closing against passage of liquid from saidlast mentioned chainber through the base to said housing, said basehaving an opening for said passage when the valve is moved against itsspring by liquid pressure a predetermined distance, a second verticalcylinder connected at its lower end to said base having liquid passagethereinto at its lower end through the base, a piston valve within saidsecond cylinder, yielding spring means normally moving said valvedownwardly to stop liquid passage through said base, and a tubeconnected at its ends to said base and upper portion of said secondcylinder for liquid passage therethrough on downward movement of saidreciprocating piston, said piston valve being elevated on increasingliquid pressure against it and stopping liquid passage through said tubewhen elevated to the point of connection of said tube to the secondcylinder.

2. The improvement having the elements in combination defined in claim1, said first cylinder having a liquid passing opening in a verticalside thereof normally covered by said reciprocating piston, above whichsaid piston is lifted on upward reciprocating movement thereof to itsuppermost position.

3. Structure having the elements in combination defined in claim 1, anda tube having a capillary passage lengthwise thereof connected at oneend to said base and located above the base within said housing,providing limited passage for liquid from said liquid chamber to saidhousing.

4. In a pump having a casing with a chamber therein for fluid to bepumped, said chamber having inlet and outlet passages with inlet andoutlet valves therein, and a yielding diaphragm comprising the upperside of said chamber, the improvement comprising a hollow verticalhousing adapted to contain liquid, located over said diaphragm andagainst its peripheral edge portions, a vertical cylinder extendingupwardly from said housing, said housing having a horizontal top at thelower end of said cylinder over and spaced from said diaphragm, therebyproviding a liquid chamber communicating with the lower end of saidcylinder, a piston in the cylinder, means for reciprocating said piston,a second vertical cylinder connected at its lower end to the top of saidhousing, said top having an opening therethrough to the lower end ofsaid second cylinder, a piston valve in the second cylinder, springmeans acting against said piston valve to normally move it to lowerposition, and a tube connected at one end to said housing top and at itsother end to said second cylinder at a point above the normal lowerposition of said piston valve, and below positions to which said pistonvalve may be lifted by liquid pressure.

5. The improvement having the elements in combination defined in claim4, said first cylinder having a liquid passing opening in a verticalside thereof normally covered by said reciprocating piston, above whichsaid piston is lifted on upward reciprocating movement thereof to itsuppermost position.

References Cited in the file of this patent UNITED STATES PATENTS1,627,257 Stevens May 3, 1927 1,650,377 Nixon Nov. 22, 1927 1,764,712Brackett June 17, 1930 2,578,746 Scherger Dec. 18, 1951 FOREIGN PATENTS50,620 France Jan. 27, 1941 597,106 Great Britain Jan. 19, 1948

